Electric curling iron



Nov. 17, 1964 M. 0. LEE ETAL ELECTRIC CURLING IRON Filed Nov. 13, 1962 INVENTORS! MLHZJEL. 0. LEE and boEoTHY b. KENDRICK A T TOE NE K5 United States Patent Tenn.

Filed Nov. 13, 1962, Ser. No. 236,832 2 illaims. (Cl. 132-37) The present invention relates to a new and improved device for curling hair and more particularly concerns an improvement in that type of curling iron which is electrically heated.

A common form of electric curling iron comprises a handle attached to a rod about which hair is adapted to be arranged, with the rod being heated by electrical means to impart a curl to the hair. The temperature of the heated rod of the curling iron is intended to attain a predetermined magnitude and cannot be controlled by the operator, other than by unplugging the curling iron from an electrical outlet supplying electrical current thereto. It has been proposed to utilize a plurality of resistance wires of varying resistance as the heating means for an electric curling iron by forming the rod to be heated as a tubular member with the resistance wires extending therein and directing electrical current through any one of the resistance wires. By switching the electrical current to pass through another resistance wire of dilferent resistance, the degree of heat transmitted to the tubular member from the heating means may be adjusted. However, the operator has no effective control over the electrical circuit including the plurality of resistance wires, since one of the resistance wires will be heated during use of the latter form of curling iron, presumably to attain its maximum operative temperature of a predetermined magnitude, and will continue to be heated unless an adjustment is made to direct the electrical current through another resistance wire. Thus, in using an electric curling iron where the rod thereof is to be heated, regardless of whether the rod is heated to attain a specific fixed temperature or a temperature which may be adjusted, the operator is obliged to rely upon the accuracy of the temperature values allegedly attainable by the electric heating means for heating the rod. If excessive heating of the rod occurs, the operator is usually unaware of this malfunction, and the electrical circuit supplying electrical current to the heating means is allowed to remain in a completed operative statethereby continuing the energization of the heating means which may result in singeing or burning of the hair.

It is therefore an object of this invention to provide a new and improved curling iron having a rod carried by a handle wherein the rod is heated by electrical means, in which the temperature of the heated rod is thermostatically controlled to open and close an electrical circuit supplying electricity to heat the rod whenever the temperature of the heated rod exceeds or falls below a predetermined magnitude.

It is another object of this invention to provide a new and improved curling iron having a rod in the form of a tube carried by a handle, wherein the tube is heated by electrical means, and including an adjustable thermostatic control mechanism extending within the heated tube for varying the degree of temperature to be attained by the heated tube, with the thermostatic control mechanism being efitective to open and close an electrical circuit supplying electricity to heat the tube whenever the temperature of the heated tube exceeds or falis below the temperature value at which the thermostatic control mechanism is adjustably set.

It is another object of this invention to provide a new 3,157,184 Patented Nov. 17, 1964 and improved curling iron having a tube carried by a handle and a heating element arranged within the interior of the tube, wherein the heating element is disposed in an electrical circuit and is energized for heating the tube, in which the electrical circuit includes movable and fixed switch contact members therein, and a thermostatic control mechanism connected to the movable switch contact member extends within the tube for regulating the move ment of the movable switch contact member into and out of engagement with the fixed switch contact member in respcnse to changes of temperature of the tube so as to complete the electrical circuit energizing the heating element Whenever the temperature or" the tube falls below a predetermined magnitude and to break the electrical circuit de-energizing the heating element whenever the temperature of the tube exceeds the predetermined magnitude.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FEGURE 1 is a side elevational view of an electric curling iron constructed in accordance with our invention;

FIGURE 2 is a fragmentary enlarged longitudinal vertical sectional view of the electric curling iron of FIGURE 1;

FEGURE 3 is a greatly enlarged transverse sectional view taken along the line 33 in FIGURE 2; and

FIGURE 4 is a greatly enlarged fragmentary transverse sectional view taken substantially along the line 44 in FIGURE 2.

Referring more specifically to the drawings, the electric curling iron in accordance with the present invention is shown as generally comprising a handle 10, a rod 11 carried by the handle it), and a clamping member 12 mounted for pivotal movement to clamp hair in place on the rod ill. The handle 14 is made of suitable insulation material and includes a longitudinal bore 13 in which electrical conductors or wires 14, 15 extend. The wire conductors 14, i5 formpart of an electrical circuit which rovides an electrical current for heating purposes, as will be subsequently described. The wire conductors 14, iii are covered by insulation material and extend outwardly of the bore 13 from the rear of the handle 10 to a suitable electrical outlet (not shown) into which they are adapted to be plugged. Referring to FIGURE 1, it will be seen that a protective resilient armor member in the form of a coiled spring 16 is secured at one end to the rear end of the handle 10 and surrounds the portion of the wire conductors 14, 15 extending outwardly of the bore 13 adjacent the rear end of the handle 10. The coiled armor spring 16 prevents undue flexing of the wire conductors 14, 15 in the region adjacent the rear end of the handle iii and shields the insulation covering thereof against damage.

The handle it is equipped with a hollow, elongated, cylindrical shank 17 having one end fixedly received with in a counterbore formed in the front end of the handle it and its other end extending forwardly of the handle Iii. One end of the rod 11 is telescopically received within the outer end of the elongated shank 17 and is frictionally secured therein to support the rod 11 in the shank 17 of the handle It). In the latter connection, the handle 16 further includes a bracket member 18, the bracket member 18 surrounding the rod 11 and comprises an annular ferrule portion 20 and an inverted U- shaped portion 21, with the annular ferrule portion 2t) bein wedged between the rod 11 and the outer end of the shank 17 to frictionally secure the end of the rod 11 within the shank 17. The inverted U-shaped portion 2i of the bracket member 18 is positioned outwardly of the shank 17 and extends about the rod ll to provide dependent cars 22, 22 for receiving the clamping member 12 to pivotally mount the clamping member 12 on the handle ill.

The rod ll of the curling iron is in the form of a tube which is illustrated as being of stepped cylindrical configuration. The tubular rod 11 includes a cylindrical mounting portion 23 frictionally secured within the shank 17 by the ferrule portion 2% of the bracket member 18 and an enlarged cylindrical barrel 24 having an outer end closed by a cap 25. A heating element 26 is mounted within the barrel 2d of the tubular rod ll. The heating element 2d comprises a cylindrical sleeve of electrically V conductive'material which is adapted to be heated by the passage of electrical current therethrough for transmitting heat to the barrel 24 of the tubular rod ll. The cylindrical heating sleeve 26 is fixed within the barrel 2-4 in radially inwardly spaced relationship therewith by annular resilient gaskets 27, 23 of insulation material, such as heat-resistant rubber, the annular gaskets 27, 23 being disposed at opposite ends of the cylindrical heating sleeve 26 and extending between the periphery of the cylindrical heating sleeve 26 and the barrel 2% to maintain radial spacing therebetween.

V The clamping member 12 comprises a jaw 29 of semicircular cross section provided with a plurality of perforations Till therein and a spring-biased lever 31 extending rearwardly at an an le from the jaw 29, the lever 31 being of generally channel-shaped construction so as to overlie the dependent ears 22, 22 of the bracket me 1: her lit in straddling relationship. The lever 31 is hingedly connected to the bracket member 18 by means of a pin 32 carried by the lever 31 and extending transversely thereof for pivotal reception within suitable apertures formed in the dependent ears 22, 22 of the bracket member 18. The rear end of the leverfill is provided with an outwardly disposed button or tab 33 of resilient insulation material, such as heat-resistant rubber. A tensioned leaf spring 34 is mounted between the lever 31 and the shank 17 of the handle lit? for biasing the rear end of the lever 31 outwardly with respect to the handle lid to urge the jaw 2% of the clamping member 12 against the barrel 24 of the tubular rod ll. In this connection, the leaf spring 34 includes one end seated on the rear end of the lever 3l beneath the button 33, with the leaf spring 34 being curved about the pin 32 and its opposite end bearing against the outer end of the shank 17. it will be understood that the application of inwardly directed manual pressure against the button 33 of the lever 31 by placing a finger thereon and pressing inwardly will cause the clamping member 12 to pivot with respect to the handle Ill about the ears 22, 22 of the bracket member lid for moving the jaw 29 away from the barrel 2d so that the hair to be curled may be arranged about the barrel 24. Upon removing the finger from the button 33 to release the inwardly directed pressure applied thereagainst, the jaw 29 of the clamping member 12 is biased toward I the barrel 24 by the leaf spring 34 to clamp the hair to be curled between the jaw 29 and the barrel 24 The electrical circuit for supplying electrical current to the cylindrical heating sleeve 26 to thereby heat the sleeve 26 for transmitting heat to the barrel 24 of the tubular rod ll includes the wire conductors l4, extending within the bore 13 provided in the handle 1%,

the wire conductor 14 being connected to a wire conductor by a flexible plate ill of electrically conductive material extending therebetween, and the wire conductor 15 I being connected to a wire conductor 42 through a switch 43 interposed in the electrical circuit and positioned within the shank 117 of the handle Hi. It will be observed that the Wire conductors it), 42 extend through the cylindrical mounting portion 23 of the tubular rod ll into the en- 4t larged cylindrical barrel 2d thereof where they are connected to the cylindrical heating sleeve 26.

The switch 43 interconnecting the wire conductor 15 with the wire conductor 42 comprises a stationary switch plate 54, one end of which is connected to the wire conductor l5 and the other end of which carries a fixed contact member 45, and a movable switch plate 46, which is connected at one end to the wire conductor 42 and carries a movable contact member 37 at its opposite end for engagement with the fixed contact member 45 carried by the stationary switch plate 44. Thus, it will be understood that engagement of the contact members 45, 4'7 closes the switch 43 to complete the electrical circuit through the cylindrical heating sleeve 26 for supplying electrical current thereto.

A cylindrical block 4% of insulation material having a forwardly extending longitudinal flange 49 is seated within the shank 17 at the rear end thereof for supporting the flexible plate 41 and the stationary switch plate 44 which extend therethrough for connection with the wire conductors l4 and 15, respectively. A substantial portion of the flexible plate 4H is disposed forwardly of the insulation block 48 for permitting flexure thereof, while the portion of the stationary switch plate 44 forwardly of the cylindrical body portion of the insulation block 48 is supported by the forwardly extending longitudinal flange 49 of the insulation block 48 which is positioned between the stationary switch plate 44- and the shank 17.

In accordance with the present invention, a thermostatic control mechanism 5% is associated with the switch 43 to regulate the opening and closing thereof for breaking and completing the electrical circuit for the cylindrical heating sleeve 26 whenever the temperature of the region including the cylindrical heating sleeve 26 and the barrel 2d of the tubular rod ill exceeds or falls below a temperature of a predetermined magnitude. In this connection, the

thermostatic control mechanism 5% comprises a first elongated substantially U-shaped thermostatic strip element 51 extending substantially throughout the tubular rod 11 and a second elongated substantially U-shaped thermostatic strip element 52 of shorter length than the first thermostatic strip element 51, with the second thermostatic strip element 52 being disposed within the barrel 24 of the tubularrod 11 in bonded superimposed relationship about the closed end portion of the first thermostatic strip element Sll. The thermostatic strip elements 51 and 52 are constructed of dissimilar metals having different coefiicients of linear expansion, the metals of the thermostatic strip elements 51 and 52 being so selected that high sensitivity to changes of temperature within the interior of the cylindrical heating sleeve 26 and the barrel 24 of the tubular rod ll is obtained. U-shaped thermostatic strip element 52 superimposed about the closed end portion of the U-shaped thermostatic strip element Sll is constructed of a selected metal having a greater coefiicient of linear expansion than the metal of the thermostatic strip element Sl. It will be observed that the forward end of the flexible plate 41 overlies the free end of the leg of the U-shaped thermostatic strip element St adjacent thereto and is secured thereto by a resilient butler element 53 of insulation material interposed therebetween and secured respectively to the thermostatic strip element 51 andthe flexible plate 4i, while the free end of the other leg of the thermostatic strip element 51 is fixedly secured to the'movable switch plate 46, within the shank 17 of the handle llll. t

in operation, the supply of electrical current to the cylindrical heating sleeve as is controlled by the expansion and contraction of the thermostatic control mechanism 5t}? comprising the U-shaped thermostatic strip elements 51, 52 which regulates the openingand closing of the switch 43 in the electrical circuit. Thus, as long as the temperature within the barrel i l-does not exceed a predetermined magnitude, the movable switch plate 46 will be disposed in the position illustrated in FIGURE 2 In this connection, the shorterwith its contact member 47 in engagement with the fixed contact member 45 to close the switch 43 for completing the electrical circuit supplying electrical current to the cylindrical heating sleeve 26. Should the temperature within the barrel 24 exceed the predetermined magnitude, the U-shaped thermostatic strip element 51 will be contracted because of the relatively greater expansion of the U-shaped thermostatic strip element 52 superimposed thereon to draw the leg of the strip element 51 carrying the movable switch plate 46 in a direction toward the opposite leg thereof against which the resilient buifer element 53 bears.

The movable switch plate 46 is accordingly moved in a direction away from the stationary switch plate 44 to space the respective contact members 47, 45 carried thereby for opening the switch 43. The opening of the switch 43 in the manner described breaks the electrical circuit supplying electrical current to the cylindrical heating sleeve 26 to permit the cylindrical heating sleeve 26 to cool. When the temperature within the barrel 24 drops below the predetermined magnitude, the U-shaped thermostatic strip element 51 will be expanded because of the relatively greater contraction of the U-shaped thermostatic strip element 52 superimposed thereon to move the leg of the strip element 51 carrying the movable switch plate 46 in a direction toward the stationary switch plate 44 for engaging the movable contact member 47 with the fixed contact member 45 to close the switch 43. The closing of the switch 43 completes the electrical circuit to again supply electrical current to the cylindrical heating sleeve 26. In this manner, electrical current is intermittently supplied to the cylindrical heating sleeve 26 through the controlling operation of the thermostatic control mechanism 50.

Means are also provided with the electric curling iron to adjust the predetermined temperature to which the thermostatic control mechanism 50 is sensitive. In this latter connection, it will be observed that a rotatable knob 60 is mounted on the shank 17 of the handle intermediate the ends thereof. The rotatable knob 60 carries an elongated threaded shaft or spindle 61 which is threadably received by an outwardly projecting hub 62 integral with the shank 17. An enlarged bumper 63 of insulation material is secured to the lower end of the spindle 61 within the hollow shank 17 for abutment with the flexible plate 41. Upon rotating the knob 60, the bumper 63 on the lower end of the spindle 61 will be moved inwardly or outwardly depending upon the direction of rotation of the knob 66, to correspondingly flex the flexible plate 41 which causes the tension in the U-shaped thermostatic strip element 51 to be changed, while moving the leg of the strip element 51 associated therewith either toward or away from the other leg of the strip element 51 to adjust the setting of the thermostatic control mechanism 50. Thus, the predetermined temperature above which and below which the thermostatic control mechanism 50 is effective to open and close the switch 43 in the manner previously described is adjustable by rotating the knob 60. Preferably, the knob 60 is provided with suitable indicia extending about its outer periphery and visible to the operator for selective alinement with an arrow or similar form of indicia provided on the outer surface of the shank 17 to permit the temperature to which the barrel 24 of the tubular rod 11 will be heated to be set at a particular value. For example, the periphery of the knob 60 may be graduated from an off position to 225 F.

It will therefore be seen that we have disclosed a new and improved electric hair curler which includes a heated tubular rod 11, wherein the temperature to be attained by the tubular rod 11 can be adjustably regulated by the operator for insuring safe operation of the hair curler without burning or singeing of the hair of the user thereof. Should the temperature of the heated tubular rod 11 become excessive, the thermostatic control mechanism 50 incorporated in our improved hair curler shuts off the electrical current to the heating element 26 contained within the heated tubular rod 11 to prevent injury to the user. Moreover, no hot spots are likely to form on the hair clamped between the heated tubular rod 11 and the jaw 29 of the clamping member 29, since the perforations 30 in the jaw 29 permit heat accumulated in the confined area of the clamped hair to be dissipated therethrough, along with any water vapor or steam emitted from wet or damp hair upon the application of heat thereto.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

We claim:

1. An electric curling iron for imparting curl to the hair of a user, said curling iron comprising (a) a handle portion of heat insulating material adapted to be held in the hand of a user,

(b) an electric circuit extending into said handle portion and adapted to be connected to a source of electrical energy,

(0) a tubular shank portion mounted at one end in said handle portion and extending outwardly therefrom,

(d) an elongate, tubular hair curling portion of larger diameter than said shank portion carried by the other end of said shank portion and extending outwardly therefrom,

(e) a tubular heating element disposed only in said hair curling portion and being in good heat conducting relation thereto, said heating element extending for a major portion of the length of said hair curling portion and being connected to said electric circuit,

(1) switch means interposed in said electric circuit to said heating element,

(g) thermostatic sensing means disposed in said hair curling portion interiorly of said tubular heating element and being connected to said switch means for controlling the temperature of said heating element and thereby said hair curling portion, and

(h) an elongate clamping member pivotally mounted on said shank portion and having a portion extending into juxtaposed cooperating relation with said hair curling portion, asid clamping being biased about its pivot in a direction to move said portion thereof into clamping relation with said hair curling portion.

2. An electric curling iron for imparting curl to the hair of a user, said curling iron comprising (a) a handle portion of heat insulating material adapted to be held in the hand of a user,

(b) an electric circuit extending into said handle portion and adapted to be connected to a source of electrical energy,

(0) an elongate, tubular shank portion mounted at one end in said handle portion and extending out- Wardly therefrom,

(d) an elongate, tubular hair curling portion of larger diameter than said shank portion and carried .by the other end of said shank portion and extending outwardly therefrom,

(e) a tubular heating element disposed only in said enlarged diameter hair curling portion and extending for a major portion of the length thereof, and having an outside diameter corresponding to a substantial degree to the inside diameter of said hair curling portion so that said heating element is closely adjacent the inside of said hair curling portion,

(f) switch means connecting said heating element to said electric circuit,

(g) thermostatic sensing means disposed in said large diameter curling portion interiorly of said tubular heating element and being connected to said switch means for controlling the temperature of said heating element and thereby said hair curling portion,

(h) control means connected to said thermostatic sensing means for varying the temperature of said heating element,

(i) a clamping member pivotally mounted on said shank portion and having a portion extending into juxtaposed cooperating relation with said hair curling portion, and

(j) spring means operatively associated. with said clamping member for biasing the same toward clamping relation with said hair curling portion.

UNITED STATES PATENTS Harper Aug. 5,

DeLangie Apr. 26,

Shelton, Dec. 5,

Sohns Dec. 14,

Harper Aug. 11,

FOREIGN PATENTS Great Britain Feb. 3,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3, 157 184 November 17 1964 Muriel 0, Lee et ala It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 45, for "asid clamping" read said clamping member Signed and sealed this 6th day of April 19650 (SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 157, 184 v November 17 1964 Muriel 0, Lee et alt.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 45, for "asid clamping" read said clamping member Signed and sealed this 6th day of April 1965,

(SEAL) Attest:

ERNEST W. SWIDER 4 EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. AN ELECTRIC CURLING IRON FOR IMPARTING CURL TO THE HAIR OF A USER, SAID CURLING IRON COMPRISING (A) A HANDLE PORTION OF HEAT INSULATING MATERIAL ADAPTED TO BE HELD IN THE HAND OF A USER, (B) AN ELECTRIC CURCUIT EXTENDING INTO SAID HANDLE PORTION AND ADAPTED TO BE CONNECTED TO A SOURCE OF ELECTRICAL ENERGY, (C) A TUBULAR SHANK PORTION MOUNTED AT ONE END IN SAID HANDLE PORTION AND EXTENDING OUTWARDLY THEREFROM, (D) AN ELONGATE, TUBULAR HAIR CURLING PORTION OF LARGER DIAMETER THAN SAID SHANK PORTION CARRIED BY THE OTHER END OF SAID SHANK PORTION AND EXTENDING OUTWARDLY THEREFROM, (E) A TUBULAR HEATING ELEMENT DISPOSED ONLY IN SAID HAIR CURLING PORTION AND BEING IN GOOD HEAT CONDUCTING RELATION THERETO, SAID HEATING ELEMENT EXTENDING FOR A MAJOR PORTION OF THE LENGTH OF SAID HAIR CURLING PORTION AND BEING CONNECTED TO SAID ELECTRIC CIRCUIT, (F) SWITCH MEANS INTERPOSED IN SAID ELECTRIC CIRCUIT TO SAID HEATING ELEMENT, (G) THERMOSTATIC SENSING MEANS DISPOSED IN SAID HAIR CURLING PORTION INTERIORLY OF SAID TUBULAR HEATING ELEMENT AND BEIING CONNECTED TO SAID SWITCH MEANS FOR CONTROLLING THE TEMPERATURE OF SAID HEATING ELEMENT AND THEREBY SAID HAIR CURLING PORTION, AND (H) AN ELONGATE CLAMPING MEMBER PIVOTALLY MOUNTED ON SAID SHANK PORTION AND HAVING A PORTION EXTENDING INTO JUXTAPOSED COOPERATING RELATION WITH SAID HAIR CURLING PORTION, ASID CLAMPING BEING BIASED ABOUT ITS PIVOT IN A DIRECTION TO MOVE SAID PORTION THEREOF INTO CLAMPING RELATION WITH SAID HAIR CURLING PORTION. 